536 
Hygienic  Laboratory  Bulletins. 
(  Am.  Jour.  Pharm. 
\  November,  1910. 
The  experimental  methods  employed  are  described  in  detail  and 
the  results  are  given  in  the  tables  in  all  cases  in  the  terms  in  which 
solubility  data  are  usually  expressed  in  the  chemical  literature,  and 
in  addition  the  equivalent  values  are  expressed  as  customarily  found 
in  the  pharmaceutical  literature,  viz.,  the  amount  of  solvent  required 
to  dissolve  a  unit  amount  of  the  dissolved  substance.  Seidell  points 
out  that  although  this  latter  mode  of  expressing  solubility  results 
has  been  used  for  many  years  by  pharmacists,  it  is  unscientific  and 
not  even  as  useful  for  practical  purposes  as  the  percentage  basis 
adopted  by  chemists.  As  an  illustration,  pharmacists  are  usually 
called  upon  to  compound  their  mixtures  in  certain  definite  amounts, 
and,  therefore,  the  quantity  of  the  dissolved  substance  which  will 
be  contained  by  the  given  volume  of  the  solution  is  certainly  of  more 
practical  interest  to  them  than  the  knowledge  of  the  amount  of  the 
solvent  required  for  one  part  of  the  given  substance.  It  would 
therefore  appear  of  considerable  advantage  to  pharmacists  to  abandon 
their  antiquated  mode  of  expressing  solubility  results  and  adopt  the 
more  rational  percentage  or  unit  of  solvent  basis  in  their  pharma- 
copoeias and  pharmaceutical  reference  books. 
Hygienic  Laboratory  Bulletin  No.  66.  I.  The  Influence  of  Age 
and  Temperature  on  the  Potency  of  Diphtheria  Antitoxin.  By 
John  F.  Anderson.  II.  An  Organism  (Pseudomonas  protect) 
Isolated  from  Water,  Agglutinated  by  the  Serum  of  Typhoid 
Fever  Patients.  By  W.  H.  Frost.  III.  Some  Considerations  on 
Colorimetry,  and  a  New  Colorimeter.  By  Norman  Roberts. 
IV.  A  Gas  Generator,  in  Four  Forms,  for  Laboratory  and 
Technical  Use.    By  Norman  Roberts,    p.  104. 
The  contents  of  this  bulletin  are  fully  indicated  by  the  titles  of 
the  several  contributions  enumerated  above. 
The  paper  by  John  F.  Anderson  is  a  comprehensive  and  timely 
review  of  work  done  on  the  keeping  qualities  of  diphtheria  antitoxin 
and  a  report  of  experiments  made  in  the  Hygienic  Laboratory  with 
18  different  lots  of  serum  furnished  by  14  different  manufacturers. 
Anderson  concludes  that :  "  The  average  yearly  loss  in  potency  of 
diphtheria  antitoxin  at  room  temperature  is  about  20  per  cent. ;  at 
150  C,  about  10  per  cent.;  at  50  C,  about  6  per  cent.,  although  in 
some  instances  these  percentages  may  be  much  increased. 
"  From  this  work,  there  appears  to  be  but  little  difference  in  the 
